Two-degree-of-freedom robust ℋ− repetitive control for grid-connected inverter

This paper presents a robust control strategy for voltage controller of grid-connected inverter. The combining of feedback-feedforward control and ℋ_∞ repetitive control is introduced to improve tracking performance and reduce the period disturbance. The achieved objective is robustly regulate voltage, good dynamic and tracking response. The proposed controller is tested in simulation by MATLAB/SIMULINK. The results show that the proposed controller obtains better performance under different scenarios (stand-alone mode, grid-connected mode and grid frequency variations) than the previous work.